In the Item 7 of Nike's 2008 10-K, review the section titled Operating Segments. Prepared a table that compares the percent change in "Total Revenue" to the change in "Pretax income" from 2007 to 2008 for the four major regions. Focus on the "Americas" region and the mention of the term leverage. How can operating leverage help explain the greater percent increase in income before taxes than the increase in total revvnues for this region?